Fig. 3

Modified EAP in rats leads to progressive bone loss. Representative µCT images of the distal apical region of the mandibular first molar of rats in two dimensions with or without induction of EAP under three time courses of observation. a Two weeks after induction, the discontinuous surface of the lamina dura (yellow frame), widened PDL (double arrow) and increased bone density (asterisk) are indicated. b Four weeks after induction, bone-loss lesion (asterisk) and slightly reduced root canal wall (yellow frame) are indicated. c Six weeks after induction, bone-loss lesion (asterisk), reduced wall thickness (blue arrow) and thickened root canal wall (yellow frame). m, mesial; d, distal; c, crown; mr, mesial root; dr, distal root (pink dotted line); f, furcation area; ap, apical bone; av, alveolar bone. Green boxes (a–c) are ROIs for bone parameter analysis (Fig. 4). Scale bar: 100 µm